However, there's another addition from a big star you may not initially recognize.

During a giant flashback at the film's start, we're introduced to King Arthur in a giant battle. His men are losing and are waiting on Merlin to come with some secret weapon. Merlin's a drunk, riding around on a horse as he throws back alcohol. But he winds up meeting with a Transformer — yes, they were on Earth that far back — and gets a special weapon in the form of a magic staff to help turn the tide.

Does Merlin look familiar? He should.
Paramount Pictures

What you may not realize is that Merlin is played by Stanley Tucci.

Take a look:

Merlin and Stanley Tucci are one and the same.
Paramount Pictures, Joel Ryan/Invision/AP | Insider composite

His character reveal is bizarre because Tucci was previously in the "Transformers" franchise as a different character. In the fourth film Tucci looked a bit more like himself while playing a tech CEO.

Stanley Tucci in "Transformers: Age of Extinction." He's been rebooted to the past!
Paramount Pictures

Tucci doesn't pull double time as two characters in "The Last Knight." He just holds the key to the Earth's future in his hands. No biggie.